The linear motion guide systems are increasingly used in recent years in a design laying their guide rails bare to the working atmosphere with no use of conventional dustproof means such as telescopic covers and bellows from the view point of increasing ample spaces to be reserved for workplace during manufacturing process and for installation of required equipments, making the guide systems themselves compact or slim in construction, cost savings on installations, and so on. Thus, many of modern linear motion guide systems are customized to have appurtenances including any special dustproof means or highly-tight sealing units to keep any foreign matter away from entering inside the slider through any ends of the slider, lubricating means to feed the slider with lubricant, and so on to increase working performance, getting the guide systems more befitting for the working environment. The linear motion guide units have become commonly used in the machine tools including material-cutting machines, grinding machines, woodcutting machines, and so on which are expected to operate especially in severe working environment where much foreign matter including dirt, chips, debris, coolants, cutting fluids occurs.
There are known linear motion guide systems with highly-tight sealing means, which are disclosed in, for example the commonly assigned Japanese Laid-Open Patent Application No. 2007-255 498. With the prior linear motion guide system, the sealing means are mounted on forward and aft ends of a slider to absolutely seal off any clearance between the guide rail and the slider that fits over the guide rail for linear sliding movement, thereby making sure of highly sealing effect to keep any foreign matter away from entering inside the slider through any ends of the slider even if in the severe working environment in which much foreign matter including dirt, chips, debris, coolants, cutting fluids occurs. The highly-tight sealing means is comprised of a cassette constituted with a front panel and an enclosure integral with the front panel, three sheets of sealing plate stowed into the cassette, and a rear panel to come into close engagement with an open edge around the enclosure. The sealing plates are each made of a three-layer structure that is composed of an intermediate spongy medium flanked by skin layers, and lubricant is forcibly absorbed in pores or cells in the intermediate layer.
The slider in the prior linear motion guide unit constructed as stated earlier, though providing much interference against the guide rail enough to make sure of durability or reliability in highly-tight sealing condition, encounters adversely large frictional resistance when it slides over the guide rail. Moreover, modern linear motion guide units are expected better sliding quality and durability even in worse working environment where splashed coolants contaminate the atmosphere.
Meanwhile, some of the linear motion guide units in recent years are expected to operate with free of maintenance for lubrication at different methods of application and therefore equip themselves with a diversity of high-functional appurtenances, which are high in accuracy, sustainable for long-lasting service life and inexpensive in cost. Often the linear motion guide units are made in the roller type high in stiffness as well as accuracy and further needed to operate with reliability in worse or severer working environment. To improve the operating quality of the linear motion guide units in the worse working environment, the slider is equipped optionally at the forward and aft ends thereof with any appurtenances including the dustproof means or highly-sealing means to keep foreign matter or contaminants against entering inside the slider through the forward and aft ends of the slider, lubricating means to feed the slider with lubricant, and so on. To this end, the slider is equipped with a mounting plate to install the appurtenances such as lubricating means to the slider with reliability and relative ease.
Moreover, when the linear motion guide unit is expected to operate in the machine tools and so on that is forced to work in the severe atmosphere where much foreign material occurs as stated earlier, it is critical for the slider to keep foreign materials lying scattered on the guide rail against entering inside the slider even in such severe atmosphere, and also continue keeping better lubrication while the slider moves back and forth over the guide rail in a sliding manner, making certain of better sliding quality with less sliding resistance.